ARF antagonizes the ability of Miz-1 to inhibit p53-mediated transactivation
ARF antagonizes the ability of Miz-1 to inhibit p53-mediated transactivation
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ARF 拮抗 Miz-1 抑制 p53 介导的反式激活的能力
DOI：
10.1038/onc.2009.372
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发表时间：
2010-02-04
期刊：
影响因子：
8
通讯作者：
Wu, M.
中科院分区：
文献类型：
--
作者：
Miao, L.;Song, Z.;Wu, M.
虽然Myc相互作用锌指蛋白-1（Miz-1）已知是一种痘病毒和Myc转录抑制所需的锌指（POZ）转录因子，但Miz-1的其他调节功能尚不清楚。使用酵母双杂交筛选，我们确定了人类交替阅读框架（ARF）蛋白作为一种新的相互作用伴侣的Miz-1。Miz-1的锌指结构域参与其与ARF的结合。此外，我们发现Miz-1能够通过其DNA结合结构域与p53相互作用，从而减少p53与其靶启动子的结合，抑制p53介导的基因转录。有趣的是，Miz-1调节的p53转录抑制不需要ARF或Mdm 2的存在。重要的是，ARF和p53被发现竞争性地结合到Miz-1在调节p53介导的转录，这一结论被验证了在体外结合试验和竞争性染色质免疫沉淀试验使用真正的p53内源性Bax和Puma启动子。因此，我们的研究表明，Miz-1通过干扰p53 DNA结合能力作为p53抑制剂，而ARF能够通过直接结合Miz-1来抵消Miz-1对p53的抑制，这表明Miz-1是ARF-p53通路中的新介质。
Although Myc-interacting zinc-finger protein-1 (Miz-1) is known to be a poxvirus and zinc-finger (POZ) transcription factor required for Myc transcriptional repression, additional regulatory function of Miz-1 is less well understood. Using a yeast two-hybrid screen, we identified human alternate reading frame (ARF) protein as a novel interaction partner of Miz-1. The zinc-finger domain of Miz-1 is involved in its binding to ARF. In addition, we found that Miz-1 was able to interact with p53 through its DNA-binding domain, thus to diminish the binding of p53 to its target promoter and inhibit p53-mediated gene transcription. Interestingly, the Miz-1-regulated p53 transcriptional suppression does not require the presence of ARF or Mdm2. Importantly, ARF and p53 were found to competitively bind to Miz-1 in regulating p53-mediated transcription, and this conclusion was verified by both in vitro binding assay and competitive chromatin immunoprecipitation assay using a bona fide p53 endogenous Bax and Puma promoters. Thus, our study reveals that Miz-1 acts as a p53 suppressor by interfering with p53 DNA-binding ability, and ARF is able to counteract the suppression of Miz-1 on p53 by direct binding to Miz-1, suggesting that Miz-1 is a novel mediator in the ARF-p53 pathway.